Accuracy assessment of GPS navigation augmented by SAR and LiDAR-derived Digital Elevation Models

Remotely sensed Digital Elevation Models(DEM)can be used to augment a standalone Global Positioning System(GPS)by adding an extra range observation which measures the distance to the Earth centre.This method so called height aiding can reduce the number of GPS satellites required to get a 3D position fix from four to three and hence improve the performance of the GPS navigation algorithm in terms of accuracy,reliability and availability.Up until now,the accuracy of height aided GPS navigation using higher resolution Synthetic Aperture Radar(SAR)and Light Detection and Ranging(LiDAR)-derived elevation data has not been fully evaluated in a broad spectrum of navigation scenarios.This article provides a robust and accurate analysis on how much range error is introduced by height aiding using 5 m spacing SAR and 1 m spacing LiDAR-derived DEMs under in-car and personal navigation situations.Based on the experimental results obtained from both dynamic and static tests,suggestions have been made on what level of vertical and positional accuracy can be achieved as well as the related DEM quality issues for navigation purposes.